For booting a computer system, a microprocessor fetches a group of boot codes from a non-volatile memory to accomplish the self-test operation and realize the basic configuration data of the system. This group of boot codes is generally so-called as a basic input output system (BIOS), and the non-volatile memory for storing the boot code, typically implemented by a flash memory, is a BIOS chip.
Please refer to FIG. 1 which schematically shows the typical arrangement of the microprocessor and the BIOS chip in the current computer structure. As shown, the microprocessor 10 fetches the boot codes stored in the BIOS chip 13 via the north-bridge chip 11, the south-bridge chip 12 and related buses. In addition to the BIOS chip 13, the computer system also includes memory devices 14 electrically connected to the north-bridge chips 11. The memory devices 14 are dynamic random access memory (DRAM) modules in conventional computer architecture. Since Micron Technology, Inc. developed a flash memory called SyncFlash®, that can reside on the same bus with DRAM and execute from a single DRAM memory controller, it is now possible to use a SyncFlash® memory as one of the memory devices 14. Under this circumstance, it is feasible to use a SyncFlash dual in-line memory module (SyncFlash DIMM) to serve as the BIOS chip 13 for storing the boot codes, and inserted in one of the slots for the memory devices 14. By this way, the microprocessor 10 can rapidly fetch the boot codes via the north-bridge chip 11.
Unfortunately, just because the SyncFlash DIMM can be inserted in any of the slots for general DRAM modules, and the module specifications of the SyncFlash DIMM and DRAM modules are identical, the SyncFlash DIMM is unidentifiable for the north-bridge chip in the booting process. In other words, the boot codes stored in the SyncFlash DIMM cannot be successfully fetched.